Volume 25, Issue 3 (September 2002)
A Laboratory Study of the Hysteresis of a Thermal Conductivity Soil Suction Sensor
An experimental program was set up to study the capillary hysteresis of the ceramic block for a newly developed thermal conductivity soil suction sensor. The testing program included two series of tests: one series of tests measured the capillary hysteresis of the ceramic blocks and the other measured the hysteresis of the relationships between the suction sensor output and the applied suctions. Test results show that there can be approximately 40% error from the correct suction value if the conventional calibration curve is used without considering the effects of capillary hysteresis. Based on the experimental testing program, a mathematical approach, which is able to take into account the effects of capillary hysteresis, was proposed when interpreting the measured soil suction data.